• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.222-228
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• 2019

An extreme value analysis (EVA) is essential to obtain a design value for highly nonlinear variables such as long-term environmental data for wind and waves, and slamming or sloshing impact pressures. According to the extreme value theory (EVT), the extreme value distribution is derived by multiplying the initial cumulative distribution functions for independent and identically distributed (IID) random variables. However, in the position mooring of DNVGL, the sampled global maxima of the mooring line tension are assumed to be IID stochastic variables without checking their independence. The ITTC Recommended Procedures and Guidelines for Sloshing Model Tests never deal with the independence of the sampling data. Hence, a design value estimated without the IID check would be under- or over-estimated because of considering observations far away from a Weibull or generalized Pareto distribution (GPD) as outliers. In this study, the IID sampling data are first checked in an EVA. With no IID random variables, an automatic resampling scheme is recommended using the block maxima approach for a generalized extreme value (GEV) distribution and peaks-over-threshold (POT) approach for a GPD. A partial autocorrelation function (PACF) is used to check the IID variables. In this study, only one 5 h sample of sloshing test results was used for a feasibility study of the resampling IID variables approach. Based on this study, the resampling IID variables may reduce the number of outliers, and the statistically more appropriate design value could be achieved with independent samples.

• Korean Management Science Review
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• v.12 no.2
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• pp.165-188
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• 1995

The conversion processes from traditional job shops to cellular manufacturing systems can be viewed as an aggregation of cause-and-effect relationships among many strategic, managerial, and technical variables. Therefore, management needs to fully understand these interacting variables and possible relationships between the variables to successfully convert their plants to cellular manufacturing systems. The purpose of this study is to assist such management's needs in part. The objectives of this research are i) investigating contingency variables that may affect the conversion processes and outcomes to cellular manufacturing systems and ii) examining relationships between the variables and the conversion processes and outcomes. In this paper, particularly three categories of variables are examined: product, process routing, and process technology / facilities characteristics. Literature review and the mail survey method are used. The results are compared and synthesized with the findings of previous studies for useful discussions. Some previous arguments and propositions are empirically supported.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1159-1161
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• 2005

This study uses a design of experiments to explain correlations between the objective function and design variables. Analysis of means, analysis of variance and table of orthogonal array were carried out. The change of shape design variable for TFLM based on the table of orthogonal array is made. Therefore this study carried to decide design variables for maximizing thrust force of TFLM. we showed improved design variables.

• Journal of Information Technology Services
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• v.15 no.2
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• pp.125-155
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• 2016

By reclassifying and reinterpreting the factor variables that were used in precedent studies on company informatization by research theme and perspective on them success factor, the present study tried to examine how different the factor variables are in frequency of use and by period, and how importantly they were considered by research theme and perspective on its success factor, combining them with the studies done on mechanism point of view. The key findings of this study are as follows. First, it was found that the frequency of using mechanism variables, which are reclassified based on SER-M perspective, has gradually increased since 1990s. While the frequency of using resource factors sharply increased in 1990s, it decreased from 2000s. It indicates that more studies were conducted of mechanism factors other than resource factors from the early 2000s. Second, when looking at those variables reclassified by research them, it was found that such theme as decision maker, environment, and resource factors were more used than other research themes in the studies on the measuring factors of informatization. Mechanism factors turned out most used among overall research themes. In particular, they were more frequently used in studies related to the performance of informatization. This result evidences that mechanism-related variables are more importantly considered in the studies than other factors. This study produces a practical implication: what factors companies have to manage and secure intensively to attain successful informatization. In addition, this study helps companies seeking informatization understand and take advantage of SER-M factors on the basis of knowledge in the transitional process of the factor variables used in studies by period. It is expected that CIO can use the key findings of this study in monitoring the factors by the stage of informatization.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.990-997
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• 2005

Many products, such as gasoline, polymer plastics, alloys, and ceramics are manufactured by mixing two or more ingredients or components. When we are to develop new mixture products, we must deal with a long list of potentially important component variables. This paper introduces some design methods for many mixture variables and some analysis tools for screening important variables out of the many candidate variables. The results of this paper will be helpful to engineers who work in the research and development sector of chemical, polymer, alloys, and electro-material industries.

• Journal of Family Relations
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• v.21 no.2
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• pp.53-75
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• 2016

Objectives: The purpose of the present study is to analysis the trends of and issues in research about parentification in Korea up to date, and to propose directions for further studies. Methods: For this purpose, eighty one theses and articles about parentification, published from 2003 to 2015 were categorized according to research subjects, research objects, research methods, statistical analysis methods, and related variables with the parentification. Results: Consequently, first, the number of articles published has been gradually increased. Second, the main research subjects were the characteristics and trait of parentification, an interpersonal relationship and family. Third, the common research objects were undergraduate student/graduate student and youth(middle/high school students). Fourth, the quantitative research methods have been used mainly. FRS-A(Filial Responsibility Scale-Adult) and FRS-Y(Filial Responsibility Scale-Youth) have been used most. A high frequency related variables with parentification were the affectiveness-related variables, in particularly, the shame proneness is the highest correlation variables. Conclusions: Based on the findings in this study, it is suggested that the research objects should be more varied and the Korean parentification measurements need to be developed in the near future.

• The Journal of Natural Sciences
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• v.17 no.1
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• pp.51-54
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• 2006

A complete convergence theorem for randomly weighted sums of random variables is obtained. No conditions are imposed on the joint distributions of the random variables.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.147-150
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• 1996

A homing torpedo's performance can be expressed a function of many variables, i.e. technical and tactical variables. When designing a homing torpedo, these variables have to be decided upon. The system effectiveness of a homing torpedo can be determined by analyzing of these variables. This paper describes a procedure of simulation metamodelling using a Factor Analysis methodology. A simulation model was used in order to obtain the data base for analyzing detection probability of torpedo. By analyzing the main and interaction effects these variables on the analysis of detection probability, we will show the importance of certain variables, of a homing torpedo.

• Korean Journal of Social Welfare
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• v.46
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• pp.263-289
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• 2001

Many studies have shown that the parents of developmentally disabled children are adversely affected by the experience of raising a child of this type. However, the range of reactions to parenting a handicapped child is quite varied and is presumably affected by a wide variety of variables. This study examined a number of demographic and psychosocial variables to determine which particular combination could best predict the current level of stress and coping behavior of mothers. Among predictor variables, marital satisfaction and dysfunctional attitude are variables that I am particularly interested in which can mediate parental stress. Five variables are found to be related to the stress of mothers, that is, level of disability, level of needed help, marital satisfaction, type of disability, father's education level. Also variables that affect four different types of stress (which are four factors of QRS-F) are analysed and the results presented. Among these variables, some are pre-determined and some are intervenable. We should make an effort to make changes in those intervenable variables such as marital satisfaction, beliefs and attitude about disability, and level of needed help. In future research we need to search and clarify the beliefs and attitude that help mothers adjust to a life with a disabled child. Also governmental support and policy making to reduce the burden of these mothers should be accompanied as well.

• Journal of Navigation and Port Research
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• v.46 no.2
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• pp.92-98
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• 2022

Maritime accidents result in enormous economic loss and loss of life; thus, such accidents must be prevented, and risks must be managed to prevent these occurrences Risk management must be based on statistical evidence such as variables. Because calculating when variables increase statistically can be difficult, compressing the designated variables is necessary to use the maritime accident data in Korea. Thus, in this study, variables of marine accident data are compressed using statistical methods. The date, ship type, and marine accident type included in all maritime accident data were extracted, the number of optimal variables was confirmed using the hierarchical clustering analysis method, and the data were compressed. For the compressed variables, the validity of the data use was statistically confirmed using analysis of variance, and the data of the variables identified using the variable compression method were designated. Consequently, among the monthly and yearly data, statistical significance was confirmed in yearly data, and compression was possible. The significance of the data was confirmed in six and eight types of ships and accidents, respectively, and these were compressed. These results can be directly used for prevention or prediction based on past maritime accident data. Additionally, the data range extracted from past maritime accidents and the number of applicable data will be studied in the future.